Replication

Replication can be configured to allow multiple OneSpan Authentication Server instances to keep their data synchronized and ensure consistency. Where multiple OneSpan Authentication Server instances use different ODBC databases as their data stores, replication ensures that each database is up-to-date with the latest data changes.

Figure: Replication with ODBC

Replicated data

The OneSpan Authentication Server replication system does not replicate the modified data itself, but instead duplicates the operations to modify the data on the replication targets. To do so, it uses special replication operations that work on user data and configuration data.

Audit data from the replication source is not replicated to the replication target, both replication instances keep and maintain their own audit data. This means that the audit data differ between the source and the target instance, although the configuration and user data are synchronized.

For instance, when a new user account is created, the source instance audits that a replication entry was successfully sent to the target instance, and the target instance audits that a replication entry was received and successfully applied (see Replication monitoring). However, the initial operation to create the user account is only audited on the source instance.

Replication queue

Replication data for all OneSpan Authentication Server instances configured as replication destinations is written to a database file (Replication.db) located in %PROGRAMFILES%\VASCO\IDENTIKEY Authentication Server\ReplData on Windows and in /var/spool/vasco/ias/ReplData on Linux, respectively.

The replication queue file has a configurable maximum size. If the file reaches this size, replication queue entries will no longer be written to the file. OneSpan Authentication Server will stop processing authentication and administration requests that result in a database update. To avoid such an interruption, you can configure OneSpan Authentication Server to send a warning message when the replication queue file size exceeds a particular size threshold before reaching the maximum size limit.

Record-level replication

The replication method used by OneSpan Authentication Server involves the replication of entire records, rather than individual record attributes. This means that data clashes can occur when a single record is updated at the same time from different sources. If this occurs, the later change will be the one chosen and written to the database. Superseded changes are ignored.